This invention relates to endoscopic surgical instruments, and in particular to powered endoscopic surgical instruments for, e.g., arthroscopy.
Powered endoscopic surgical instruments typically include a stationary outer tube within which an inner tube that carries a surgical tool on its distal end is rotated by a motor. Body tissue exposed to the surgical tool through an opening in the outer tube is cut by the rotating tool. Tissue fragments cut by the tool and irrigating fluid from the surgical site are drawn through an interior suction passage in the inner tube in response to suction applied at the proximal end of the instrument. Several such surgical instruments are described in U.S. Pat. Nos. 4,203,444, 4,274,414, 4,834,729, 4,842,578, 4,983,179, and 5,322,505, all of which are assigned to the assignee of the present invention and incorporated herein by reference.
The configuration of the surgical tool is typically a function of the type of body tissue to be cut. For example, in instruments for cutting relatively soft tissue (such as cartilage and synovial tissue), the tool is a blade formed by sharpened edges of a window in the inner tube which cooperates with sharpened edges of the outer tube opening as the inner tube rotates. In an "abrader" for sculpting bone tissue, the surgical tool is a solid, fluted burr the proximal shank of which is mounted on the inner tube. The burr includes a series of axially elongated, inclined cutting edges spaced circumferentially around the burr by the flutes. A slot in the burr shank conveys bone fragments cut by the burr and irrigation fluid into the interior passage of the inner tube for removal by the applied suction.